Greater Western Sydney (2012–2024) Haynes was drafted by
Greater Western Sydney with their sixth selection and seventh overall in the
2011 national draft. He made his debut in Greater Western Sydney's inaugural season, in
2012, playing in round ten of the season against
Geelong at
Kardinia Park where he had eight disposals (six kicks and two handballs), three marks and five tackles in a 65-point loss. In 2013, Haynes signed on for a new two year contract after a rookie season where Haynes self admittedly struggled. In the
2017 AFL Season during round six, Haynes suffering a hamstring tendon tear against the
Western Bulldogs, which ruled him out for about ten weeks. Haynes landed awkwardly in the splits position following a one-on-one marking contest late in the final quarter at
Manuka Oval. The
2018 AFL Season saw Haynes put together what was regarded as his breakout season after a multiple injury interrupted seasons. Haynes was ranked eleventh in the competition for intercepts with 158 in his 24 appearances. Giants coach
Leon Cameron said Haynes, has added more elements to his game over the past couple of seasons, and was quoted as saying, "I think he gets undervalued for the amount of run he provides. He's a chop-out marking specialist and every club wants to have one of those players, because marking is gold when you're starting your attack (from defence). But his ability to cover the ground this year has been phenomenal, as has his ability to beat his man one-on-one.". In 2019, Haynes signed a five year deal to keep him at the Giants till 2024. Haynes had a career best season during the
2020 AFL Season where he was awarded a debut
All-Australian selection on a half back flank. He also won the
Kevin Sheedy Medal as the club's
best and fairest player, tied with
Lachie Whitfield.
Carlton (2024–present) After 13 years at the Giants, Haynes departed as a free agent and moved to on a one-year deal. He had a strong first season with the Blues, coming fourth in the 2025
John Nicholls Medal count. In September of 2025, Haynes signed a one-year contract extension to the end of 2026. ==Personal life==